Field of the Invention
The present invention relates to wireline logging and, more particularly, in one or more embodiments, the present invention relates to a device for improving the conveyance of wireline logging tools down irregular and/or deviated boreholes.
Background of the Invention
Wireline logging is a common operation in the oil industry whereby down-hole electrical tools are conveyed on wireline (also known as “e-line” in industry parlance) to evaluate formation lithologies and fluid types in a variety of boreholes. In irregular shaped boreholes, characterized by variations in hole size with depth, and/or in deviated boreholes, there can be problems in conveying wireline logging tools to total well depth since the bottom of the tool-string may impact upon certain features in the borehole, such as ledges, washouts, or contractions. In this situation full data acquisition from total well depth may not be possible and remedial action may be required, either altering the borehole conditions for more favorable descent or improving the tool-string geometry to navigate past the obstructions; either way may be costly to the well operator.
Consequently, there is a need for improving wireline tool-string geometry to aid conveyance past ledges, washouts, and contractions which may be present in irregular shaped and/or deviated boreholes.